U.S. patent application number 17/049144 was filed with the patent office on 2021-08-05 for tubular fabric and base material for medical use using same.
This patent application is currently assigned to Toray Industries, Inc.. The applicant listed for this patent is Toray Industries, Inc.. Invention is credited to Nobuaki Tanaka, Satoshi Yamada.
Application Number | 20210238774 17/049144 |
Document ID | / |
Family ID | 1000005593767 |
Filed Date | 2021-08-05 |
United States Patent
Application |
20210238774 |
Kind Code |
A1 |
Tanaka; Nobuaki ; et
al. |
August 5, 2021 |
TUBULAR FABRIC AND BASE MATERIAL FOR MEDICAL USE USING SAME
Abstract
Provided is a tubular fabric that has a homogeneous structure
along its outer circumference and excellent shape-stability and
that is useful as hoses for transferring a fluid or powder or for
protecting linear materials such as a wire, a cable, and a conduit,
tubular filters, and medical base materials such as an artificial
blood vessel. The tubular fabric includes a wall part that is woven
by interlacing a warp yarn and a weft yarn and that has a double
weave structure, a weft yarn in an outer layer and a weft yarn in
an inner layer being not intersected with each other. The tubular
fabric preferably has a circularity c of 0.8 or more and 1.2 or
less, the circularity c being represented by the following equation
of an outer diameter b perpendicular to an outer diameter a with
respect to the outer diameter a, the outer diameter a being
obtained by measuring a location corresponding to a fabric width A
in weaving of the tubular fabric. Circularity c=a/b
Inventors: |
Tanaka; Nobuaki; (Osaka-shi,
Osaka, JP) ; Yamada; Satoshi; (Otsu-shi, Shiga,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toray Industries, Inc. |
Tokyo |
|
JP |
|
|
Assignee: |
Toray Industries, Inc.
Tokyo
JP
|
Family ID: |
1000005593767 |
Appl. No.: |
17/049144 |
Filed: |
April 12, 2019 |
PCT Filed: |
April 12, 2019 |
PCT NO: |
PCT/JP2019/015929 |
371 Date: |
October 20, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/06 20130101; D03D
1/00 20130101; D03D 11/02 20130101; D03D 3/02 20130101 |
International
Class: |
D03D 3/02 20060101
D03D003/02; D03D 1/00 20060101 D03D001/00; D03D 11/02 20060101
D03D011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2018 |
JP |
2018-085164 |
Claims
1. A tubular fabric comprising a wall part that is woven by
interlacing a warp yarn and a weft yarn and has a double weave
structure, wherein a weft yarn in an outer layer and a weft yarn in
an inner layer are not intersected with each other.
2. The tubular fabric according to claim 1, having a circularity c
of 0.8 or more and 1.2 or less, wherein the circularity c is
represented by a following equation 1 of an outer diameter b
perpendicular to an outer diameter a with respect to the outer
diameter a, and the outer diameter a is obtained by measuring a
location corresponding to a fabric width A in weaving of the
tubular fabric: Circularity c=a/b (equation 1).
3. The tubular fabric according to claim 1, having a repulsive
ratio Fc of 0.8 or more and 1.2 or less, wherein the repulsive
ratio Fc is represented by a following equation 2 of a repulsive
force Fb under compression along the outer diameter b of the
tubular fabric by a distance one-half the outer diameter b with
respect to a repulsive force Fa under compression along the outer
diameter a of the tubular fabric by a distance one-half the outer
diameter a: Repulsive ratio Fc=Fa/Fb (equation 2).
4. The tubular fabric according to claim 1, satisfying a following
equation 3: (L2-L1)/L1.gtoreq.0.1 (equation 3), wherein L1 is a
gauge-line distance between gauge lines that is obtained under
compression in a warp direction of the tubular fabric at a stress
of 0.01 cN/dtex, the gauge lines being drawn on an outer
circumference of the tubular fabric, with a distance five times a
maximum value of an outer diameter of the tubular fabric measured
without application of a stress to the tubular fabric; and L2 is a
gauge-line distance under elongation in the warp direction at a
stress of 0.01 cN/dtex.
5. The tubular fabric according to claim 1, comprising no accordion
structure.
6. The tubular fabric according to claim 1, wherein the warp yarn
and the weft yarn used in the tubular fabric are synthetic
fibers.
7. The tubular fabric according to claim 1, wherein the synthetic
fibers used as the warp yarn and/or the weft yarn are polyester
having a fracture elongation of 70% or less.
8. The tubular fabric according to claim 1, wherein a synthetic
fiber exposed to an inner surface constituting the tubular fabric
is a multifilament whose single-yarn diameters are partially or
entirely 5 .mu.m or less.
9. The tubular fabric according to claim 1, wherein synthetic
fibers in the outer layer constituting the tubular fabric are
partially or entirely monofilaments having a diameter of 20 .mu.m
or more.
10. A medical base material comprising the tubular fabric according
to claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is the U.S. National Phase application of
PCT/JP2019/015929, filed Apr. 12, 2019, which claims priority to
Japanese Patent Application No. 2018-085164, filed Apr. 26, 2018,
the disclosures of each of these applications being incorporated
herein by reference in their entireties for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to a tubular fabric. The
present invention more specifically relates to a tubular fabric
that includes a wall part having a double weave structure.
BACKGROUND OF THE INVENTION
[0003] Tubular fabrics are being used for various industrial
applications such as a hose, a reinforcing material, and a
protection material, and multilayer-structure fabrics are being
proposed having a complicated weave structure according to the
application.
[0004] For example, Patent Document 1 proposes a thick belt that is
formed of four or more layers and is a bag-shaped fabric formed
using two weft shuttles.
[0005] Patent Document 2 proposes a two-pronged tube-shaped fabric
produced using a needle loom, and Patent Document 3 proposes an
artificial blood vessel tubularly woven using one weft yarn.
[0006] Further, Patent Document 4 discloses a two-layer tubular
fabric that is less uneven on an inner surface of the tubular
fabric, has excellent stretchability, softness, and kink resistance
(easy flexibility), and is suitable for artificial blood
vessels.
PATENT DOCUMENTS
[0007] Patent Document 1: Japanese Patent Laid-open Publication No.
06-184857
[0008] Patent Document 2: Japanese Patent Laid-open Publication No.
08-80342
[0009] Patent Document 3: Japanese Patent No. 2779456
[0010] Patent Document 4: WO 2018/066476 A
SUMMARY OF THE INVENTION
[0011] However, the multilayer-structure fabric of Patent Document
1 is woven in a bag shape but is not one utilized after processing
into a tubular shape. Further, the shuttles of the loom are placed
back and forth, forcing the weft yarn fed by the back shuttle to
always pass only above or below the front shuttle to give a fabric
always having intersection of the weft yarns at either one of the
left or the right of the fabric. Therefore, weaving in a tubular
shape leads to a result of impairing, at the intersection portion,
the homogeneity along the outer circumference of the tubular
fabric. For example, a tubular fabric, such as an artificial blood
vessel, produced using this technique has had a possibility of
varying the property of puncture along the outer circumference.
[0012] On the other hand, the tube-shaped fabric described in
Patent Document 2 is a technique for weaving a two-pronged
tube-shaped fabric by alternately inserting a first needle and a
second needle of a needle loom. The tube-shaped fabric, however,
includes one layer as a fabric layer, so that the technique also
has a problem of shape-stability.
[0013] The self-supporting tube-shaped knitted or woven artificial
blood vessel described in Patent Document 3 has a plain-weave
structure and is formed of one layer as a structure, so that the
technique also has a problem of shape-stability.
[0014] Further, weaving of the tubular fabric described in Patent
Document 4 with a normal shuttle loom causes mutual intersection of
weft yarns in layers, so that the intersection portion has
similarly had poor homogeneity along the outer circumference.
[0015] Accordingly, an object of the present invention is to
provide a tubular fabric that has a homogeneous structure along its
outer circumference and that includes an excellent shape-stability
wall part having a double weave structure.
[0016] In order to solve the above problems, the present invention
according to exemplary embodiments is configured as follows.
[0017] (1) A tubular fabric including a wall part that is woven by
interlacing a warp yarn and a weft yarn and has a double weave
structure, in which a weft yarn in an outer layer and a weft yarn
in an inner layer are not intersected with each other.
[0018] (2) The tubular fabric according to (1), having a
circularity c of 0.8 or more and 1.2 or less, in which the
circularity c is represented by a following equation 1 of an outer
diameter b perpendicular to an outer diameter a with respect to the
outer diameter a, and the outer diameter a is obtained by measuring
a location corresponding to a fabric width A in weaving of the
tubular fabric.
Circularity c=a/b (equation 1)
[0019] (3) The tubular fabric according to (1) or (2), having a
repulsive ratio Fc of 0.8 or more and 1.2 or less, in which the
repulsive ratio Fc is represented by a following equation 2 of a
repulsive force Fb under compression along the outer diameter b of
the tubular fabric by a distance one-half the outer diameter b with
respect to a repulsive force Fa under compression along the outer
diameter a of the tubular fabric by a distance one-half the outer
diameter b.
Repulsive ratio Fc=Fa/Fb (equation 2)
[0020] (4) The tubular fabric according to any one of (1) to (3),
satisfying a following equation 3.
(L2-L1)/L1.gtoreq.0.1 (equation 3)
[0021] L1 is a gauge-line distance between gauge lines that is
obtained under compression in a warp direction of the tubular
fabric at a stress of 0.01 cN/dtex, the gauge lines being drawn on
an outer circumference of the tubular fabric, with a distance five
times a maximum value of an outer diameter of the tubular fabric
measured without application of a stress to the tubular fabric.
[0022] L2 is a gauge-line distance under elongation in the warp
direction at a stress of 0.01 cN/dtex.
[0023] (5) The tubular fabric according to any one of (1) to (4),
having no accordion structure.
[0024] (6) The tubular fabric according to any one of (1) to (5),
in which the warp yarn and the weft yarn used in the tubular fabric
are synthetic fibers.
[0025] (7) The tubular fabric according to any one of (1) to (6),
in which the synthetic fibers used as the warp yarn and/or the weft
yarn are polyester having a fracture elongation of 70% or less.
[0026] (8) The tubular fabric according to any one of (1) to (7),
in which a synthetic fiber exposed to an inner surface constituting
the tubular fabric is a multifilament whose single-yarn diameters
are partially or entirely 5 .mu.m or less.
[0027] (9) The tubular fabric according to any one of (1) to (8),
in which synthetic fibers in the outer layer constituting the
tubular fabric are partially or entirely monofilaments having a
diameter of 20 .mu.m or more.
[0028] (10) A medical base material containing the tubular fabric
according to any one of (1) to (9).
[0029] According to the present invention, a tubular fabric is
obtained that has a homogeneous structure along its outer
circumference and that includes an excellent shape-stability wall
part having a double weave structure. According to a further
preferable aspect of the present invention, a tubular fabric is
obtained that has an almost true circle as the sectional shape and
that further has a good shape-retaining ability.
[0030] The tubular fabric of the present invention is usefully
applicable to hoses for transferring a fluid or powder or for
protecting linear materials such as a wire, a cable, and a conduit,
tubular filters, and medical base materials such as an artificial
blood vessel, a shunt, and a stent graft. A medical base material
of the present invention has a homogeneous structure along the
outer circumference of the tubular fabric when grafted as an
artificial blood vessel, has the same property of puncture in any
location to allow easy sewing, and also has an excellent
shape-retaining ability to enable rapid suture in an operation.
According to a further preferable aspect of the present invention,
the tubular fabric has an almost true circle as its sectional shape
to have more excellent ease of sewing and a more excellent
shape-retaining ability and thus exhibit a more excellent effect in
an operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is an explanatory diagram of a gray fabric completely
woven as a tubular fabric.
[0032] FIG. 2 is an explanatory diagram of a base material obtained
by completely processing the tubular fabric.
[0033] FIG. 3 is a conceptual diagram of a device for measuring the
repulsive force of the tubular fabric.
[0034] FIG. 4 is an explanatory diagram for drawing gauge lines on
the tubular fabric.
[0035] FIG. 5 is a conceptual diagram of a device for measuring the
gauge-line distance under compression of the tubular fabric.
[0036] FIG. 6 is a conceptual diagram of a device for measuring the
gauge-line distance under elongation of the tubular fabric.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0037] A tubular fabric according to embodiments of the present
invention is a tubular fabric including a wall part that is woven
by interlacing a warp yarn and a weft yarn and that has a double
weave structure, the tubular fabric being characterized in that a
weft yarn in an outer layer and a weft yarn in an inner layer are
not intersected with each other.
[0038] The phrase "the weft yarns in the layers are not intersected
with each other" means that the weft yarn placed in the outer layer
and the weft yarn placed in the inner layer are not interlaced when
a double weft fabric is tubularly woven, to allow no inner-layer
weft yarn to appear on a surface of the tubular fabric. The term
"double weave structure" means that the weave structure is double
and refers to double weft weave where the weft yarn is double and
to double warp and weft weave where both the warp yarn and the weft
yarn are double.
[0039] The tubular fabric configured above has a homogeneous
structure along the outer circumference of a section across the
long axis at the tubular wall part having the double weave
structure, and has excellent shape-stability. Particularly, when
grafted as an artificial blood vessel, the tubular fabric has the
same property of puncture in any location along the outer
circumference of the tubular fabric and has excellent
shape-stability to allow easy sewing.
[0040] It is preferable to use a synthetic fiber for the warp yarn
and the weft yarn used in the tubular fabric of the present
invention. Specific examples of such a synthetic fiber include a
nylon fiber and a polyester fiber, and a polyester fiber is
preferable in terms of strength and dimensional stability. Examples
of the polyester fiber include a fiber formed of, for example,
polyethylene terephthalate, polybutylene terephthalate,
polypropylene terephthalate, or a copolymer thereof.
[0041] The synthetic fiber preferably has a fracture elongation of
70% or less in terms of strength and shape-stability. The synthetic
fiber has a fracture elongation of further preferably 60% or less,
more preferably 50% or less, and the lower limit is 10% or
more.
[0042] The fiber constituting the warp yarn in the tubular fabric
has a total fineness of preferably 560 dtex or less, further
preferably 235 dtex or less, more preferably 100 dtex or less, in
terms of strength and shape-stability, and the lower limit is 10
dtex or more.
[0043] The weave density based on a warp yarn A that is measured by
cutting open the tubular fabric is preferably 200 yarns/inch (2.54
cm) or less, further preferably 180 yarns/inch (2.54 cm) or less,
more preferably 150 yarns/inch (2.54 cm) or less, in terms of
strength and shape-stability, and the lower limit is 20 yarns/inch
(2.54 cm) or more.
[0044] The fiber constituting the weft yarn in the tubular fabric
has a total fineness of preferably 560 dtex or less, further
preferably 235 dtex or less, more preferably 100 dtex or less, in
terms of strength and shape-stability, and the lower limit is 10
dtex or more.
[0045] The weave density based on each of the inner-layer weft yarn
and the outer-layer weft yarn that is measured by cutting open the
tubular fabric is preferably 200 yarns/inch (2.54 cm) or less,
further preferably 180 yarns/inch (2.54 cm) or less, more
preferably 150 yarns/inch (2.54 cm) or less, in terms of strength
and shape-stability, and the lower limit is 20 yarns/inch (2.54 cm)
or more.
[0046] The tubular fabric has an inner diameter of preferably 100
mm or less, further preferably 50 mm or less, more preferably 10 mm
or less, in terms of shape-stability. A preferable lower limit is
about 1.5 mm in terms of weaving performance.
[0047] The method for producing the tubular fabric of the present
invention is not particularly limited as long as the method gives
the tubular fabric specified in the present invention. The tubular
fabric of the present invention, however, is preferably woven using
a shuttle loom with two or more shuttles placed back and forth on
the cloth-fell end and the beam end of the loom, so as to form a
tubular wall part having the double weave structure. That is, the
tubular fabric is preferably woven so as to form a quadruple fabric
having a quadruple weave structure, with no connection point
provided but a hollow formed between the second layer and the third
layer. In the weaving, a total of two shuttles are used that are a
shuttle for weft insertion of the weft yarn constituting the outer
layer (hereinafter also sometimes referred to as an outer-layer
weft yarn) and a shuttle for weft insertion of the weft yarn
constituting the inner layer (hereinafter also sometimes referred
to as an inner-layer weft yarn). Each of the shuttles are used for
weft insertion while allowed to make a round trip on a rail.
[0048] In the weaving of the tubular fabric, when the weft
insertion is performed by conventional methods with respect to a
shedding part between the warp yarns, using the shuttles placed
back and forth on the cloth-fell end and the beam end, with the
cloth-fell-end shuttle used for the inner layer and the beam-end
shuttle used for the outer layer of the tubular fabric, the weft
yarn supplied by the back shuttle always passes above the
cloth-fell-end shuttle to cause the inner-layer weft yarn to be
intersected with the outer-layer weft yarn and thus be exposed on a
surface of the tubular fabric. However, switching the positions of
the front and back shuttles in the weft insertion causing the
exposure of the inner-layer weft yarn enables weft insertion
causing no intersection of the inner-layer weft yarn with the
outer-layer weft yarn.
[0049] Further, the tubular fabric of the present invention
preferably has a circularity c of 0.8 or more and 1.2 or less, more
preferably 0.85 or more and 1.15 or less, the circularity c being
represented by the following equation of an outer diameter b
perpendicular to an outer diameter a with respect to the outer
diameter a, the outer diameter a being obtained by measuring, in a
tubular fabric 2 processed as shown in FIG. 2, a location
corresponding to a fabric width A in the weaving of a tubular
fabric (gray fabric) 1 as shown in FIG. 1.
Circularity c=a/b
[0050] Setting the relationship between the outer diameters a and b
in the above range leads to the tubular fabric being a true circle
or having a shape close to the true circle, to enable provision of
the tubular fabric allowing easy sewing with a tubular material
having the same diameter.
[0051] In embodiments of the present invention, the cross-sectional
outer circumferential part of the wall part constituting the
tubular fabric has a homogeneous structure, so that appropriate
adjustment of the material and the fineness of the fiber, the weave
density, and the outer diameter and the inner diameter of the
tubular fabric so as to impart proper repulsive force to the
tubular fabric enables an improvement in the circularity of the
cross-sectional outer circumferential part. The repulsive force can
be increased, for example, by using a stiffer fiber as the material
for the fiber or by increasing the single-yarn fineness, the total
fineness, or the weave density. It is possible to increase the
repulsive force by forming the tubular fabric with use of, for
example, a fiber having a high single-yarn fineness, e.g., a
monofilament (a diameter of preferably 20 .mu.m or more, more
preferably 40 .mu.m or more, and the upper limit is 150 .mu.m or
less). Further, by forming the tubular fabric with use of fibers at
least a part of which is a fiber having a low single-yarn fineness,
it is possible to make the structure homogeneous and dense, thus
improving the homogeneity of the cross-sectional outer
circumferential part of the wall part and thus also increase the
circularity. The fiber having a low single-yarn fineness described
above is preferably a multifilament whose single-yarn diameters are
partially or entirely 5 .mu.m or less. The single-yarn diameter is
more preferably 4 .mu.m or less, and the lower limit is 1 .mu.m or
more. Setting the single-yarn diameter in the above range improves
the softness of the tubular fabric to enable formation of a denser
structure. Further, it is also possible to further increase the
repulsive force and thus increase the circularity by a method for
using a fiber having a high single-yarn fineness, e.g., a
monofilament (preferably a diameter of 20 .mu.m or more, more
preferably 40 .mu.m or more, and the upper limit is 150 .mu.m or
less) in combination with the above or by a method for decreasing
the outer diameter or the inner diameter of the tubular fabric.
Then, a round rod having an outer diameter fitted to the dimension
of the inner diameter of these woven tubular fabrics is inserted
into a hollow of the tubular fabric and the tubular fabric is
heat-set to be shrunk and thus be set in a shape along the round
rod, so that the tubular fabric having a circularity in the above
range can easily be obtained.
[0052] A heat-setting condition is preferably 60.degree. C. or more
higher, more preferably 80.degree. C. or more higher than the glass
transition temperature of the material used, and is preferably
20.degree. C. or more lower, more preferably 30.degree. C. or more
lower than the melting point of the material used. Setting the
heat-setting temperature in the above range allows an excellent
heat setting property and proper shrinkage to enable formation of
the shape along the shape of the core rod and thus acquisition of
the tubular fabric having excellent shape-stability.
[0053] Further, the ratio of a repulsive force Fb under compression
along the outer diameter b of the tubular fabric by a distance
one-half the outer diameter b to a repulsive force Fa under
compression along the outer diameter a of the tubular fabric by a
distance one-half the outer diameter a, that is, the repulsive
ratio Fc represented by the following equation is preferably 0.8 or
more and 1.2 or less, more preferably 0.85 or more and 1.15 or
less.
Repulsive ratio Fc=Fa/Fb
[0054] Setting the relationship between the repulsive forces Fa and
Fb in the above range enables provision of the tubular fabric
having an excellent shape-retaining ability and has excellent kink
resistance (easy flexibility) even when flexed.
[0055] In embodiments of the present invention, the cross-sectional
outer circumferential part of the wall part constituting the
tubular fabric has a homogeneous structure to enable acquisition of
the tubular fabric having small anisotropic repulsive force.
Appropriate adjustment of the weave density, and the outer diameter
and the inner diameter of the tubular fabric so as to give further
proper repulsive force enables a much more decrease of the
repulsive ratio. Then, a round rod having an outer diameter fitted
to the dimension of the inner diameter of the tubular fabric woven
is inserted into a hollow of the tubular fabric and the tubular
fabric is heat-set to be shrunk and thus increase the repulsive
force, so that the tubular fabric having a repulsive ratio in the
above range can easily be obtained.
[0056] Further, the tubular fabric according to embodiments of the
present invention is characterized in that the relationship between
a gauge-line distance L1 between gauge lines and a gauge-line
distance L2 between the gauge lines is represented by the following
equation, the gauge lines being drawn with a distance five times
the outer-diameter maximum part of the tubular fabric measured
without application of a stress to the tubular fabric, the
gauge-line distance L1 being a gauge-line distance under
compression in a warp direction of the tubular fabric at a stress
of 0.01 cN/dtex, and the gauge-line distance L2 being a gauge-line
distance under elongation in the warp direction at a stress of 0.01
cN/dtex.
(L2-L1)/L1.gtoreq.0.1
[0057] The value of the formula (L2-L1)/L1 is preferably 0.15 or
more, more preferably 0.18 or more, in terms of further improving
the stretchability and the softness of the tubular fabric. The
upper limit is preferably 1.0.
[0058] Setting the relationship between the gauge-line distances L1
and L2 in the above range enables provision of the tubular fabric
having excellent stretchability, softness, and kink resistance
(easy flexibility). That is, when the tubular fabric is bent to be
flexed, a stress is applied onto an inner circumferential side of
the flexed tubular fabric in the compression direction and
simultaneously onto an outer circumferential side in the elongation
direction. Setting the relationship in the above range, however,
enables the outer circumference to be sufficiently elongated with
respect to the inner circumference, which means that the tubular
fabric has excellent kink resistance. An elongation operation or a
compression operation at a stress of 0.01 cN/dtex corresponds to a
stress normally generated when a person manually elongates or
compresses the tubular fabric with a soft touch in the warp
direction, and the tubular fabric having a relationship in the
above range means that the tubular fabric has good operability also
in a flexure operation performed by a person and has excellent
stretchability and softness. In the tubular fabric designed so as
to have stretchability and softness as described above, designing
the weft yarns in the layers not to be intersected with each other
makes the tubular fabric more effective than a tubular fabric
having a similar weave design, in terms of further improving the
stretchability represented by (L2-L1)/L1.
[0059] The tubular fabric of the present invention preferably has
an elongation of 30% or less when elongated at a stress of 0.01
cN/dtex in the warp direction, in terms of allowing a person to
feel a response when manually pulling the tubular fabric with a
soft touch. The tubular fabric has an elongation of further
preferably 20% or less, more preferably about 10%. The tubular
fabric has, as the lower limit, an elongation of preferably 5% or
more, more preferably 8% or more, in terms of allowing a person to
feel a sense of elongation when manually pulling the tubular fabric
with a soft touch. The tubular fabric having an elongation in the
above range has good operability for allowing a person to manually
perform sewing and is soft, so that the tubular fabric has the same
property of puncture in any location along the outer circumference
of the tubular fabric when grafted as an artificial blood
vessel.
[0060] The tubular fabric preferably has no accordion structure.
The tubular fabric having no accordion structure has no unevenness
on the inner surface, generating no turbulent flow even when a
fluid is flowed in a narrow space and generating no turbulent flow
of blood when used as a particularly narrow artificial blood vessel
or shunt, to have an advantage of being less likely to produce a
blood clot.
[0061] The phrase "having no accordion structure" refers to a
tubular fabric having no structure obtained by inserting a core rod
with a spiral or annular wave groove into the tubular fabric and
heating the tubular fabric for wave setting or to a non-pleated
tubular fabric. For formation of the tubular fabric having no
accordion structure, it is desirable to finish the tubular fabric
without using the core rod with a spiral or annular wave groove
described above. Particularly, the tubular fabric is preferably
heat-set using a round rod as the core rod inserted.
[0062] Further, in embodiments of the present invention, use of a
fiber having a low elongation, for example, a fracture elongation
of 70% or less as a fiber used in the tubular fabric also enables
impartation of the stretchability to the tubular fabric itself.
[0063] Such a tubular fabric can be produced as follows, for
example.
[0064] In a weaving step, as the warp yarns, at least two types of
yarns (a warp yarn A and a warp yarn B) are preferably used. These
warp yarns are also preferably fibers having a fracture elongation
of 70% or less as described above. The fibers have a fracture
elongation of further preferably 60% or less, more preferably 50%
or less, and the lower limit is 10% or more. Such fibers are
different from an elastic yarn having so-called rubber elasticity
and are normally recognized as non-elastic yarns in this
industry.
[0065] The warp yarn A can be formed of various synthetic fibers
such as a nylon fiber and a polyester fiber. Especially, a
polyester fiber that is a non-elastic yarn is preferable in terms
of strength and dimensional stability. Examples of the polyester
fiber that is a non-elastic yarn include a fiber formed of, for
example, polyethylene terephthalate, polybutylene terephthalate,
polypropylene terephthalate, or a copolymer thereof.
[0066] Here, the warp yarn A that is a synthetic fiber exposed to
the inner surface constituting the tubular fabric may be an
ultrathin fiber obtained by direct spinning or may be an ultrathin
fiber obtained by subjecting a sea-island composite fiber to a sea
removal treatment. Especially, the synthetic fiber in the warp
direction that is exposed to the inner surface is preferably a
multifilament whose single-yarn diameters are partially or entirely
5 .mu.m or less. Setting the single-yarn diameters in the above
range improves the softness of the tubular fabric and enables
formation of a denser structure, so that the tubular fabric can be
expected to cover an endothelial cell when used as an artificial
blood vessel or a shunt.
[0067] The warp yarn B is preferably formed of a soluble yarn. The
soluble yarn is a fiber soluble in solvents such as water and an
alkaline solution. As specific examples of the soluble yarn, it is
possible to use water-soluble fibers such as a polyvinyl alcohol
fiber; and easily alkali-soluble fibers such as a polyester fiber
containing a third copolymerized component, i.e., isophthalic acid,
5-sodiumsulfoisophthalic acid, or methoxy polyoxyethylene glycol,
and a polylactic acid fiber. The soluble yarn, however, is not
particularly limited. As the warp yarn B, it is also possible to
use a temporary yarn to be removed after weaving.
[0068] The warp yarns each have a total fineness of preferably 560
dtex or less, further preferably 235 dtex or less, more preferably
100 dtex or less, and the lower limit is 10 dtex or more.
[0069] The weave density based on the warp yarn A that is measured
by cutting open the tubular fabric of the present invention is
preferably 200 yarns/inch (2.54 cm) or less, further preferably 180
yarns/inch (2.54 cm) or less, more preferably 150 yarns/inch (2.54
cm) or less, and the lower limit is 20 yarns/inch (2.54 cm) or
more.
[0070] As the weft yarns, at least two types of yarns (a weft yarn
C and a weft yarn D) are preferably used.
[0071] In this case, a tubular fabric having a double structure is
preferably formed. A preferable aspect of this case is that the
weft yarn C is positioned in the inner layer, and the weft yarn D
is position in the outer layer of the tubular fabric.
[0072] The weft yarn C positioned in the inner layer and the weft
yarn D positioned in the outer layer are, for example, formed of
various synthetic fibers such as a nylon fiber and a polyester
fiber but are preferably non-elastic yarns. Especially, a polyester
fiber that is a non-elastic yarn is preferable in terms of strength
and dimensional stability. Examples of the polyester fiber that is
a non-elastic yarn include a fiber formed of, for example,
polyethylene terephthalate, polybutylene terephthalate, or
polypropylene terephthalate.
[0073] The yarns have a fracture elongation of preferably 70% or
less, further preferably 60% or less, more preferably 50% or less,
and the lower limit is 10% or more.
[0074] The weft yarn C positioned in the inner layer and exposed to
the inner surface can be an ultrathin fiber obtained by subjecting
a sea-island composite fiber to a sea removal treatment or by
direct spinning, using, as an original yarn, the sea-island
composite fiber or the ultrathin fiber obtained by direct spinning.
These synthetic fibers as the weft yarn C are each preferably a
multifilament whose single-yarn diameters are partially or entirely
5 .mu.m or less. The single-yarn diameter is more preferably 4
.mu.m or less, and the lower limit is 1 .mu.m or more. Setting the
single-yarn diameter in the above range improves the softness of
the tubular fabric and enables formation of a denser structure, so
that the tubular fabric can be expected to be covered by an
endothelial cell when used as an artificial blood vessel or a
shunt.
[0075] The weft yarn D positioned in the outer layer is preferably
a monofilament having a single-yarn diameter of 20 .mu.m or more.
The weft yarn D has a single-yarn diameter of more preferably 40
.mu.m or more, and the upper limit is 150 .mu.m or less. Setting
the single-yarn diameter in the above range improves the stiffness
of the inner layer and thus improves the repulsive force of the
tubular fabric. Setting the single-yarn diameter in the above range
also suppress degradation of the tubular fabric caused by
hydrolysis to enable an improvement of the durability of the
tubular fabric.
[0076] The weft yarns each have a total fineness of preferably 560
dtex or less, further preferably 235 dtex or less, more preferably
100 dtex or less, and the lower limit is 10 dtex or more.
[0077] The weave density based on each of the weft yarns C and D
that is measured by cutting open the post-processed tubular fabric
is preferably 200 yarns/inch (2.54 cm) or less, further preferably
180 yarns/inch (2.54 cm) or less, more preferably 150 yarns/inch
(2.54 cm) or less, and the lower limit is 20 yarns/inch (2.54 cm)
or more.
[0078] The weft insertion method for not causing intersection
between the inner-layer weft yarn and the outer-layer weft yarn in
the weaving of the tubular fabric is, for example, a method for
using a shuttle loom with two or more shuttles placed back and
forth on the cloth-fell end and the beam end of the loom and
switching the positions of the front and back shuttles in the weft
insertion causing the exposure of the inner-layer weft yarn.
[0079] In the weaving, the tubular fabric is preferably woven, with
the warp yarn B placed at high tension, and the warp yarn A placed
at low tension within a range not to adversely affect the shed of
the loom. For example, the warp yarn B preferably has a tension of
0.5 to 1.5 cN/dtex, and the warp yarn A preferably has a tension of
0.05 to 0.15 cN/dtex. The placement of the warp yarns A and B is
preferably placement at a ratio of the warp yarn A to the warp yarn
B of 2 to 10 yarns/1 yarn.
[0080] As regards a high-density fabric, lowering the tension of
the warp yarn in the weaving to increase the crimp ratio of the
warp yarn generally makes it difficult to increase the weft density
due to bumping (slack pick). The embodiment described above,
however, enables the weft yarn to be firmly held by the warp yarn A
while the warp yarn B serving as a fulcrum, and thus enables
suppression of the bumping. Therefore, the crimp ratio of the warp
yarn A can be increased, and removal of the warp yarn B after the
weaving enables impartation of the softness to the tubular
fabric.
[0081] The warp yarn B is preferably placed between the weft yarn C
positioned in the inner layer and the weft yarn D positioned in the
outer layer.
[0082] The use of at least two types of weft yarns, i.e., the weft
yarn C position in the inner layer and the weft yarn D positioned
in the outer layer of the tubular fabric generates structural
strain due to their different perimeters. The structural strain
enables impartation of an elongation property to the tubular
fabric. According to the embodiment described above, the weft yarns
C and D are not intersected with each other to enable the
cross-sectional outer circumferential part of the wall part to have
a homogeneous structure, so that the tubular fabric has the same
property of puncture in any location along the outer circumference
of the tubular fabric when grafted as an artificial blood vessel,
and has excellent shape-stability.
[0083] The tubular fabric has an inner diameter of preferably 100
mm or less, further preferably 50 mm or less, more preferably 10 mm
or less. A preferable lower limit is about 1.5 mm in terms of
weaving performance.
[0084] The post-processing step preferably includes the following
steps, for example. In the following embodiment, an example is a
tubular fabric having an inner diameter of 3.3 mm.
[0085] (a) Hot Water Washing
[0086] Hot water washing removes original-yarn oil and shrink the
warp yarn B. The treatment conditions are preferably a temperature
of 80 to 98.degree. C. and a time of 15 to 40 minutes.
[0087] (b) Pre-Heat Setting
[0088] Pre-heat setting stabilizes the shape of the warp yarn A
having increased its crimp ratio along with the shrinkage of the
warp yarn B. A round rod having an outer diameter of 3.0 mm is
inserted into the tubular fabric, and the tubular fabric is fixed
at both ends with a wire or the like, and heat-treated. The outer
diameter of the round rod used is appropriately selected according
to the degree of shrinkage of the woven tubular fabric by the
pre-heat setting. The treatment conditions are preferably a
temperature of 160 to 190.degree. C. and a time of 3 to 10 minutes.
The material for the round rod is, for example, steel use stainless
(SUS).
[0089] (c) Sea Removal Treatment
[0090] The warp yarn A and the weft yarn C are subjected to a sea
removal treatment as necessary, and the warp yarn B is removed by
dissolution.
[0091] The sea removal treatment and the removal by dissolution are
performed by the following steps.
[0092] (c-1) Acid Treatment
[0093] An acid treatment embrittles a sea component of the
sea-island composite fiber. The acid is, for example, maleic acid.
The treatment conditions are preferably a concentration of 0.1 to
1% by mass, a temperature of 100 to 150.degree. C., and a time of
10 to 50 minutes. When the sea-island composite fiber is not used,
the acid treatment can be avoided.
[0094] (c-2) Alkali Treatment
[0095] An alkali treatment elutes the soluble yarn and the sea
component of the sea-island composite fiber having been embrittled.
The alkali is, for example, sodium hydroxide. The treatment
conditions are preferably a concentration of 0.5 to 2% by mass, a
temperature of 70 to 98.degree. C., and a time of 60 to 100
minutes.
[0096] (d) Heat Setting 1 (First Time)
[0097] First heat setting is aimed at re-maximizing the crimps of
the warp yarn loosened by the sea removal treatment. A round rod
having an outer diameter of 3.3 mm is inserted into the tubular
fabric, and the tubular fabric is fixed at both ends with a wire or
the like while maximally compressed in the warp direction so as not
to allow wrinkles on the tubular fabric, and is heat-treated. The
treatment conditions are preferably a temperature of 160 to
190.degree. C. and a time of 3 to 10 minutes. The material for the
round rod is, for example, steel use stainless (SUS).
[0098] (e) Heat Setting (Second Time)
[0099] Second heat setting is aimed at forming a fabric that has a
shrinkage margin while retaining flexing points of the crimps. The
second heat setting, however, need not be performed. A round rod
having an outer diameter of 3.3 mm is inserted into the tubular
fabric, and the tubular fabric is fixed at both ends with a wire or
the like while elongated by 20 to 50% in the warp direction, and is
heat-treated. The treatment conditions are preferably a temperature
of 10 to 20.degree. C. lower than in the first heat setting, and a
time of 3 to 10 minutes. The round rod is, for example, SUS.
[0100] The tubular fabric obtained as described above includes the
wall part whose cross-sectional outer circumferential part has a
homogeneous structure, and the tubular fabric has excellent
shape-stability. In a particularly preferable aspect, the tubular
fabric has an almost true circle as the shape of a section cut
along the diameter, is less uneven on the inner surface, and has
excellent stretchability, softness, kink resistance (easy
flexibility), shape-retaining ability, and repulsive force, and the
tubular fabric is usefully applicable to hoses for transferring a
fluid or powder or for protecting linear materials such as a wire,
a cable, and a conduit, tubular filters, and medical base materials
such as an artificial blood vessel and is suitably usable
particularly as an artificial blood vessel.
EXAMPLES
[0101] Hereinafter, the present invention is described with
reference to examples and comparative examples.
[0102] The methods for measuring various properties used in the
present examples are as follows.
[0103] (1) Fineness and Number of Filaments
[0104] The fineness was measured in compliance with fineness based
on corrected mass (method A) in JIS L 1013: 2010 8.3.1.
[0105] The number of filaments was measured on the basis of JIS L
1013: 2010 8.4.
[0106] (2) Single-Yarn Diameter
[0107] The single-yarn diameter was measured on the basis of a
photograph of lateral surfaces of single yarns in a multifilament
used and a lateral surface of a monofilament used, the photograph
being taken with microscope VHX-200 (manufactured by KEYENCE
CORPORATION) at 100 to 400-fold magnification. The single-yarn
diameter was calculated in the unit of .mu.m. In the measurement, a
modified cross-section yarn such as a flat yarn was measured at the
part where its lateral surface was minimum.
[0108] (3) Inner Diameter of Tubular Fabric
[0109] The inner diameter of the tubular fabric was measured in
accordance with the guidance of ISO7198 by vertically standing a
circular cone with a taper ratio of 1/10 or less, vertically and
softly dropping the tubular fabric onto the circular cone so that
the section cut along the diameter of the tubular fabric covered
the circular cone, and measuring the diameter of the circular cone
at the position where the lower end of the sample stopped.
[0110] The tubular fabric was cut at 50-mm intervals in the warp
direction, measured at five locations, and evaluated according to
the average of the measured values.
[0111] (4) Outer Diameter of Tubular Fabric
[0112] The outer diameter of the tubular fabric was measured with a
caliper.
[0113] The tubular fabric was measured at five locations with 50-mm
intervals in the warp direction without application of a stress to
the tubular fabric, and evaluated according to the average of the
measured values.
[0114] (5) Repulsive Force of Tubular Fabric
[0115] FIG. 3 is a conceptual diagram of a device for measuring the
repulsive force of the tubular fabric.
[0116] A repulsive force 6 was measured by using compression rate
and compressive elastic modulus measuring device SE-15 manufactured
by INTEC CO., LTD., attaching a 10 cm.sup.2 compression table 4 of
a sample retaining ring stand and a 5 cm.sup.2 gauge head 3 to the
device, putting a sample, or a processed tubular fabric 2 on the
compression table 4, setting the gauge head at 0 in the position
where the gauge head was brought into contact with an upper part of
the sample to the extent not to deform the shape of the tubular
fabric, and then compressing the sample in an arrow-5 direction by
the distance one-half the diameter of the sample.
[0117] (6) Weave Density of Cut-Open Tubular Fabric
[0118] The weave density was measured in compliance with JIS L
1096: 2010 8.6.1.
[0119] A sample obtained by cutting open the tubular fabric was put
on a flat table, unnatural wrinkles and tension were removed, the
number of warp yarns and weft yarns in a length of 0.5 cm was
counted at five different locations, and the average value of each
of the warp yarn and the weft yarn was calculated and converted to
the number of yarns per 2.54 cm.
[0120] (7) Fracture Elongation
[0121] The fracture elongation was measured under the
constant-rate-of-elongation conditions specified in the
normal-state test of JIS L 1013: 2010 8.5.1. A sample was measured
using "TENSILON" UCT-100 manufactured by ORIENTEC CORPORATION, at a
holding interval of 25 cm and a tensile speed of 30 cm/min.
[0122] (8) Gauge-Line Distance L1 Under Compression and Gauge-Line
Distance L2 Under Elongation of Tubular Fabric
[0123] First, the maximum value of the outer diameter of the fabric
(the outer-diameter maximum part of the tubular fabric measured
without application of a stress to the tubular fabric) is
determined by the above (4).
[0124] Next, FIG. 4 is an explanatory diagram for drawing gauge
lines on the tubular fabric. As shown in FIG. 4, a first gauge line
8 is drawn on the outer circumference of a tubular fabric 7 at a
position 5 mm away from one edge of the tubular fabric. A second
gauge line 9 is drawn on the outer circumference of the tubular
fabric, with a distance X five times the maximum value of the outer
diameter of the tubular fabric from the first gauge line. The
tubular fabric 7 is cut along the diameter at a position 5 mm away
from the second gauge line.
[0125] FIG. 5 is a conceptual diagram of a device for measuring the
gauge-line distance under compression of the tubular fabric. As
shown in FIG. 5, the device includes HANDY DIGITAL FORCE GAUGE HF-1
((rated capacity: 10 N) manufactured by Japan Instrumentation
System Co., Ltd.) that serves as a force gauge 10 and is fitted on
a platform 11, a core rod portion-equipped compression chuck jig 12
attached to the force gauge 10, and a compression receiving jig 13
having a hole into which the core rod portion is insertable and
being attached to the platform 11.
[0126] Then, the tubular fabric 7 was set in the device by
inserting the core rod portion of the compression chuck jig 12 into
the tubular fabric 7, and the gauge-line distance L1 under
compression (gauge-line distance under compression) at a stress of
0.01 cN/dtex in the warp direction was measured with a caliper.
[0127] Here, the core rod portion of the compression chuck jig 12
that is inserted into the tubular fabric 7 has a diameter of the
inner-diameter minimum part of the tubular fabric 7 -0.1 mm
(.+-.0.03 mm), and the hole of the compression receiving jig 13 has
the same diameter as the inner-diameter minimum part of the tubular
fabric. Here, the same diameter does not have to be strictly the
same diameter, but a difference of about .+-.0.03 mm is to be
regarded as the same diameter. FIG. 6 is a conceptual diagram of a
device for measuring the gauge-line distance under elongation of
the tubular fabric. As shown in FIG. 6, the device includes HANDY
DIGITAL FORCE GAUGE HF-1 ((rated capacity: 10 N) manufactured by
Japan Instrumentation System Co., Ltd.) that serves as a force
gauge 10 and is fitted on a platform 11, an elongation chuck jig 14
attached to the force gauge 10, and an elongation receiving jig 15
attached to the platform 11. The tubular fabric 7 was fixed at its
outer sides of the gauge lines with fixing cords 16, and the
gauge-line distance L2 under elongation (gauge-line distance under
elongation) at a stress of 0.01 cN/dtex in the warp direction was
measured with a caliper.
[0128] The measurement was performed five times with different
samples, and the tubular fabric was evaluated by the average of the
measured values.
[0129] The stress was calculated by the following equation.
Stress (cN)=0.01.times.warp-yarn fineness.times.number of warp
yarns
Example 1
[0130] In the weaving step, the following warp yarns (the warp yarn
A and the warp yarn B) and weft yarns (the weft yarn C and the weft
yarn D) were used. [0131] Warp yarn A (sea-island composite fiber):
Polyethylene terephthalate fiber, 66 dtex, 9 filaments (after sea
removal treatment: 52.8 dtex, 630 filaments) [0132] Warp yarn B
(soluble yarn): Easily alkali-solution polyester fiber containing
copolymerized 5-sodiumsulfoisophthalic acid, 84 dtex, 24 filaments
[0133] Weft yarn C (inner layer) (sea-island composite fiber):
Polyethylene terephthalate fiber, 66 dtex, 9 filaments (after sea
removal treatment: 52.8 dtex, 630 filaments) [0134] Weft yarn D
(outer layer): Polyethylene terephthalate fiber, 44 dtex,
monofilament
[0135] When the weft insertion was performed in the weaving, with
the cloth-fell-end shuttle set as the weft yarn C and the beam-end
shuttle set as the weft yarn D, a tubular fabric was woven while
the positions of the front and back shuttles were switched in the
weft insertion that causes exposure of the weft yarn C to the
outside of the weft yarn D. A tubular fabric having an inner
diameter of 3.3 mm was woven at a tension of the warp yarn B of 0.9
cN/dtex and a tension of the warp yarn A of 0.1 cN/dtex, to have a
weave density measured by cutting open the post-processed tubular
fabric of 136 yarns/inch (2.54 cm) for the warp yarn A, 120
yarns/inch (2.54 cm) for the weft yarn C, and 120 yarns/inch (2.54
cm) for the weft yarn D. The warp yarns A and B were placed at a
ratio of the three warp yarns A to the one warp yarn B. The warp
yarn B was placed between the weft yarn C positioned in the inner
layer and the weft yarn D positioned in the outer layer.
[0136] Next, post processing was performed by the following
steps.
[0137] (a) Hot Water Washing
[0138] The treatment conditions were a temperature of 98.degree. C.
and a time of 20 minutes.
[0139] (b) Pre-Heat Setting
[0140] A round rod having an outer diameter of 3.0 mm was inserted
into the tubular fabric, and the tubular fabric was fixed at both
ends with a wire and heat-treated. The treatment conditions were a
temperature of 180.degree. C. and a time of 5 minutes. The material
for the round rod was SUS.
[0141] (c) Sea Removal Treatment
[0142] The warp yarn A and the weft yarn C were subjected to a sea
removal treatment, and the warp yarn B was removed by
dissolution.
[0143] (c-1) Acid Treatment
[0144] Maleic acid was used as an acid. The treatment conditions
were a concentration of 0.2% by mass, a temperature of 130.degree.
C., and a time of 30 minutes.
[0145] (c-2) Alkali Treatment
[0146] Sodium hydroxide was used as an alkali. The treatment
conditions were a concentration of 1.0% by mass, a temperature of
80.degree. C., and a time of 90 minutes.
[0147] (d) Heat Setting (First Time)
[0148] A round rod having an outer diameter of 3.3 mm was inserted
into the tubular fabric, and the tubular fabric was fixed at both
ends with a wire or the like while maximally compressed in the warp
direction so as not to allow wrinkles on the tubular fabric, and
was heat-treated. The treatment conditions were a temperature of
180.degree. C. and a time of 5 minutes. The material for the round
rod was SUS.
[0149] (e) Heat Setting (Second Time)
[0150] A round rod having an outer diameter of 3.3 mm was inserted
into the tubular fabric, and the tubular fabric was fixed at both
ends with a wire or the like while elongated by 30% in the warp
direction, and was heat-treated. The treatment conditions were a
temperature of 170.degree. C. and a time of 5 minutes. The material
for the round rod was SUS.
[0151] Table 1 shows the properties of the resultant tubular
fabric.
[0152] The resultant tubular fabric had good operability when
manually flexed, and had excellent stretchability, softness,
repulsive property, and shape-retaining ability. The tubular fabric
had no accordion structure. No weft yarn C was exposed to the outer
surface of the tubular fabric. When sewn with each other, the
tubular fabrics had the same property of puncture in any location
along the outer circumference of the tubular fabrics and had an
almost true circle as the section cut along the diameter of the
tubular fabrics to allow much easier sewing than of the tubular
fabric obtained in Comparative Example 1 described later.
Example 2
[0153] A tubular fabric was obtained similarly to Example 1 except
that the inner diameter of the tubular fabric was set at 4.0 mm and
the second heat setting was not performed.
[0154] The resultant tubular fabric had good operability when
manually flexed, and had excellent stretchability, softness,
repulsive property, and shape-retaining ability. No weft yarn C was
exposed to the outer surface of the tubular fabric. When sewn with
each other, the tubular fabrics had the same property of puncture
in any location along the outer circumference of the tubular
fabrics and had an almost true circle as the section cut along the
diameter of the tubular fabrics to allow much easier sewing than of
the tubular fabric obtained in Comparative Example 2 described
later.
Example 3
[0155] A tubular fabric was obtained similarly to Example 1 except
that the inner diameter of the tubular fabric was set at 5.0 mm and
the second heat setting was performed at an elongation of 20%.
[0156] The resultant tubular fabric had good operability when
manually flexed, and had excellent stretchability, softness,
repulsive property, and shape-retaining ability. No weft yarn C was
exposed to the outer surface of the tubular fabric. When sewn with
each other, the tubular fabrics had the same property of puncture
in any location along the outer circumference of the tubular
fabrics and had an almost true circle as the section cut along the
diameter of the tubular fabrics to allow much easier sewing than of
the tubular fabric obtained in Comparative Example 2 described
later.
Example 4
[0157] A tubular fabric was obtained similarly to Example 1 except
that a tubular fabric having an inner diameter of 3.3 mm was woven,
with the warp yarn A used in place of the warp yarn B (soluble
yarn) of the tubular fabric and the tension of all the warp yarns
set at 0.5 cN/dtex, to have a weave density measured by cutting
open the post-processed tubular fabric of 130 yarns/inch (2.54 cm)
for the warp yarn A, 90 yarns/inch (2.54 cm) for the weft yarn C,
and 90 yarns/inch (2.54 cm) for the weft yarn D, and except that
the second heat setting was not performed.
[0158] The resultant tubular fabric had an excellent repulsive
property and an excellent shape-retaining ability. No weft yarn C
was exposed to the outer surface of the tubular fabric. When sewn
with each other, the tubular fabrics had the same property of
puncture in any location along the outer circumference of the
tubular fabrics and had an almost true circle as the section cut
along the diameter of the tubular fabrics to allow easier sewing
than of the tubular fabric obtained in Comparative Example 3
described later.
Comparative Example 1
[0159] A tubular fabric was obtained similarly to Example 1 except
that the tubular fabric was woven without switching the positions
of the cloth-fell-end shuttle, the weft yarn C and the beam-end
shuttle, the weft yarn D in the weaving.
[0160] In the resultant tubular fabric, a part where the weft yarns
were intersected with each other was protruded from the contour of
the tubular fabric even after the heat setting was performed with
the round rod inserted into the tubular fabric, and the tubular
fabric had poor circularity. Also from the viewpoint of the
physical properties, the tubular fabric had poor flexure at the
part where the weft yarns were intersected with each other, and had
a poor balance of a perpendicular repulsive property. Further, when
the tubular fabrics were sewn with each other, the base materials
were hard at the part where the weft yarns were intersected with
each other, and had trouble being sewn with each other.
Comparative Example 2
[0161] A tubular fabric was obtained similarly to Example 2 except
that the tubular fabric was woven without switching the positions
of the cloth-fell-end shuttle, the weft yarn C and the beam-end
shuttle, the weft yarn D in the weaving and was woven using, as the
weft yarns C and D, the same type of yarn, a polyethylene
terephthalate fiber, 66 dtex, 9 filaments (after sea removal
treatment: 52.8 dtex, 630 filaments).
[0162] In the resultant tubular fabric, a part where the weft yarns
were intersected with each other was protruded similarly to
Comparative Example 1, and the part had poor flexure and a poor
balance of a perpendicular repulsive property. Further, when the
tubular fabrics were sewn with each other, the base materials were
hard at the part where the weft yarns were intersected with each
other, and had trouble being sewn with each other.
Comparative Example 3
[0163] A tubular fabric was obtained similarly to Example 4 except
that the tubular fabric was woven without switching the positions
of the cloth-fell-end shuttle, the weft yarn C and the beam-end
shuttle, the weft yarn D in the weaving.
[0164] In the resultant tubular fabric, a part where the weft yarns
were intersected with each other was protruded even after the heat
setting was performed with the round rod inserted into the tubular
fabric, and the part had poor flexure and a poor balance of a
perpendicular repulsive property. Further, when the tubular fabrics
were sewn with each other, the base materials were hard at the part
where the weft yarns were intersected with each other, and had
trouble being sewn with each other.
TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Example
1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3 Type
of warp yarn A -- Polyethylene Polyethylene Polyethylene
Polyethylene Polyethylene Polyethylene Polyethylene terephthalate
terephthalate terephthalate terephthalate terephthalate
terephthalate terephthalate Fineness of warp dtex 52.8 52.8 52.8
52.8 52.8 52.8 52.8 yarn A Number of filaments filaments 630 630
630 630 630 630 630 in warp yarn A Fracture elongation % 30.4 30.4
30.4 30.4 30.4 30.4 30.4 of warp yarn A Single-yarn diameter
.mu.m.phi. 2.78 2.78 2.78 2.78 2.78 2.78 2.78 of warp yarn A Type
of weft yarn C -- Polyethylene Polyethylene Polyethylene
Polyethylene Polyethylene Polyethylene Polyethylene terephthalate
terephthalate terephthalate terephthalate terephthalate
terephthalate terephthalate Fineness of weft dtex 52.8 52.8 52.8
52.8 52.8 52.8 52.8 yarn C Number of filaments filaments 630 630
630 630 630 630 630 in weft yarn C Fracture elongation % 30.4 30.4
30.4 30.4 30.4 30.4 30.4 of warp yarn C Single-yarn diameter
.mu.m.phi. 2.78 2.78 2.78 2.78 2.78 2.78 2.78 of weft yarn C Type
of weft yarn D -- Polyethylene Polyethylene Polyethylene
Polyethylene Polyethylene Polyethylene Polyethylene terephthalate
terephthalate terephthalate terephthalate terephthalate
terephthalate terephthalate Fineness of weft dtex 44 44 44 44 44
52.8 44 yarn D Number of filaments filaments 1 1 1 1 1 630 1 in
weft yarn D Fracture elongation % 32.1 32.1 32.1 32.1 32.1 32.1
32.1 of warp yarn D Single-yarn diameter .mu.m.phi. 63.72 63.72
63.72 63.72 63.72 2.78 63.72 of weft yarn D Outer diameter a
mm.phi. 3.77 4.52 5.48 3.92 4.12 4.91 4.42 Outer diameter b mm.phi.
3.73 4.42 5.31 3.82 3.32 3.84 3.53 Circularity c = a/b -- 1.01 1.02
1.03 1.03 1.24 1.28 1.25 Repulsive force Fa cN 49.4 48.4 47.3 51.2
53.7 29.4 55.9 Repulsive force Fb cN 47.8 47.6 46.9 49.8 42.8 24.1
41.6 Repulsive ratio Fc = -- 1.03 1.02 1.01 1.03 1.25 1.22 1.34
Fa/Fb Gauge-line distance mm 18.9 22.6 27.4 19.6 20.6 24.6 22.1
Gauge-line distance mm 16.3 21.7 25.6 19.5 19.2 22.4 22.0 under
compression (L1) Gauge-line distance mm 20.8 26.8 31.0 19.7 21.3
25.9 22.2 under elongation (L2) (L2 - L1)/L1 -- 0.28 0.24 0.21 0.01
0.11 0.16 0.01
[0165] A tubular fabric of the present invention is suitably usable
as an artificial blood vessel, but the application range of the
tubular fabric is not limited to the artificial blood vessel.
DESCRIPTION OF REFERENCE SIGNS
[0166] 1: Tubular fabric (gray fabric) in weaving [0167] 2:
Processed tubular fabric [0168] 3: Gauge head [0169] 4: Compression
table [0170] 5: Arrow [0171] 6: Repulsive force [0172] 7: Tubular
fabric [0173] 8: First gauge line [0174] 9: Second gauge line
[0175] 10: Force gauge [0176] 11: Platform [0177] 12: Compression
chuck jig [0178] 13: Compression receiving jig [0179] 14:
Elongation chuck jig [0180] 15: Elongation receiving jig [0181] 16:
Fixing code [0182] A: Fabric width [0183] X: Gauge-line distance
five times maximum value of outer diameter of fabric [0184] a:
Outer diameter of processed base material (location corresponding
to fabric width A in gray fabric) [0185] b: Outer diameter of
processed base material (fabric thickness in gray fabric)
* * * * *